Water mains blowing up is a regular occurrence in the States and guess what you can shut them off. If you think that a single water main or even a group of mains caused this dramatic crisis then you are ignoring what Irans government is not only saying as of now but for years. You cant blame this on a single incident even the the Supreme Leader has been saying they are facing this threat since 2011. Also what about the second most populous city? Its at dead water level already.